Fixed the test to not use an epsilon

clippy_lints/src/unused_rounding.rs

@@ -42,7 +42,7 @@ fn is_useless_rounding(expr: &Expr) -> Option<(&str, String)> {
             } else {
                 ""
             };
-            if f.fract() < f64::EPSILON {
+            if f.fract() == 0.0 {
                 Some((method_name, f_str))
             } else {
                 None

tests/ui/unused_rounding.fixed

@@ -5,4 +5,5 @@ fn main() {
     let _ = 1f32;
     let _ = 1.0f64;
     let _ = 1.00f32;
+    let _ = 2e-54f64.floor();
 }

tests/ui/unused_rounding.rs

@@ -5,4 +5,5 @@ fn main() {
     let _ = 1f32.ceil();
     let _ = 1.0f64.floor();
     let _ = 1.00f32.round();
+    let _ = 2e-54f64.floor();
 }